稀土元素对软氮化层抗冲击磨损性能的影响

The Effect of Rare Earth Elements on Impact Wear-Resistance of Soft Nitriding Layer

作者利用La和Ce加特定溶剂对7Cr_7Mo_3V_2Si和4Cr_3Mo_3(?)两种模具钢进行了常规软氮化和稀土软氮化处理,冲击磨损试验结果证明,稀土软氮化层的冲击韧性和抗冲击磨损性能都比常规软氮化层的好。稀土软氮化处理的自行车螺钉热镦模具的使用寿命分别为常规软氮化和未经表面处理的两倍和4倍以上。通过扫描电子显微镜对冲击磨损表面形貌的观察发现,常规软氮化层发生了大块磨屑剥落,而稀土软氮化层发生的是小层片状磨屑剥离,并就软氮化层的冲击磨损机理进行了探讨。

In this paper two die steels 7Cr7Mo3V2Si and 4Cr3Mo3W4 VNb were chemically heat-treated by means of conventional soft nitriding and RE(Rare Earth)-soft nitriding, in which La, Ce and special solvent were added. The results of impact wear tests showed that the impact toughness and impact wear-resistance of the RE nitriding layers are better than the conventional nitriding layers'. The life time of a RE-nitrided hot die for screw of bicycles was increased about 1 and 3 times than that of conventionally nitrided dies. It has been also found through observation of impact wear surfaces on SEM that the larger wear debris are often flaked off from the conventional nitriding layers, whereas that from RE-nitriding layers are much smaller. Finally, the impact wear mechanism of RE-nitriding layers was discussed.